Electrical switching mechanism



April 13, 1937. sp 2,076,923

ELECTRICAL SWITCHING MECHANISM Filed Sept. 6, 1955 INVENTOR.

5 4 W%WM ATTORNEYS.

Patented Apr. 13, 1937 UNITED STATES ELECTRICAL SWITCHING MECHANISM Emil Spahn, Zug, Switzerland, assignor to Landis & Gyr, A-G., a corporation of Switzerland- Application September 6, 1935, Serial No. 39,399 In Switzerland September 28, 1934 3 Claims.

The invention relates to electric contact devices and more especially to electrical switching mechanisms employing a mercury tube switch.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawing, referred to herein and constituting a part hereof, illustrates one embodiment of the invention, and together with the description, serves to explain the principles of the invention.

Of the drawing:

Fig. 1 is an elevation of a mechanism embodying the invention; and

Fig. 2 is a vertical section on line 2-2 of Fig. 1.

The invention is directed to providing new and improved electrical contact mechanisms which are especially adapted for use in devices where the available driving power is small, as in clocks, electrical measuring apparatus such as meters, and the like. The invention is particularly desir able for such devices because it provides a very small and very uniform loading on the driving 30 means, and at the same time insures reliable making'of the contact and long life of the contact mechanism. It will be understood that the invention in its broader aspects is of general application, but that its special advantages adapt it particularly for use with devices of the type indicated by way of example.

Broadly described, the preferred form of the invention comprises a mercury switch tube which is adapted'to be rapidly oscillated to and fro from one tilted position to the other to effect quick and positive making and breaking of the circuit. The oscillation of the tube is effected by novel means which require very little power and a substantially continuous application of said low driving force. As preferably embodied, continuouslyoperating drive means are connected to tube-tilting members in such a manner that the rotation of the drive means imparts potential energy to 50 the tilting device by raising it while it is restrained from rotational or tilting movement. At a predetermined point the tilting device is released to rotate and tilt the tube, while the driving member continues its movement, again picking up the tilting member and raising it until it has suf- (Cl. ZOO-36) ficient energy to again rotate to reverse the tilt of the tube.

It will be understood that the foregoing general description and the following detailed description as well are exemplary and explanatory of the invention but are not restrictive thereof.

Referring now in detail to the present preferred embodiment of the invention illustrated by way of example in the accompanying drawing, a mercury switch tube ll) of a known type is mounted for oscillatory tilting movement between frame plates l and 2 of an electric meter mechanism or the like. The tube III is hung in a suitable carrier frame ll, formed of insulating material, the frame being fixedly mounted on stud shafts l2 which extend transversely to the tube and are trunnioned at either end in the frame plates l and 2.

Suitable electric connections are made between the mercury switch tube Ill and connecting strips mounted in the frame plates of the mechanism. As embodied, the tube is provided with recesses l3 in the lower portion of the tube for containing the electrodes to be connected by the mercury in predetermined positions of the tube. Terminal or connecting strips 14 are attached to and insulated from the frame plates l and 2 of the mechanism by insulating plates l5 which are riveted to the frame plates l and 2 and support the connecting strips l4 within recesses 16 formed in said plates I and 2. The connecting strips M are suitably fastened to the insulating plates 15 by screws 1! which serve as bearings for the shaft I2 of the carrier frame H. Electrical connection is made between the electrodes in the recesses I3 and the shaft l2 through metal shields 25 at either end of the carrier frame II and the electrical cables 2| which lead from the recesses within the tube.

Means are provided for resiliently balancing the tiltable tube H) on shaft 12, comprising oppositely acting spiral springs 23, one end of which is fixed to the ends of the shaft l2, the outer ends of said springs being fixed to the terminal strips M, as by metal pins 24. The springs 23 thus serve to balance the tube in a neutral position and also act as auxiliary means for carrying current from the shaft I2 to the terminal strips 14.

Referring now to the embodied means for oscillatably tilting the tube HI about the axis l2, an upwardly extending arm 30 rises from the carrier frame II and is provided with a relatively long vertical slot 3| in its upper portion. The means for imparting a to and fro or oscillatory movement to the member comprises a crank 32 fixed to and rotatable with a shaft 33, said crank having at its free end a pin 34 which is adapted to travel in the slot 3|.

The embodied means for actuating the crank 32 to oscillate the tube comprises a main drive shaft which is rotated by a continuously driven crown gear 4|. A second shaft 43 is continuously rotated from shaft 40 through reduction gearing 44 and 45.

The shaft 33 is freely suspended from the shaft 43 by arms which are free to swing about the shaft 43, and the shaft 33 is journaled to turn freely in the outer ends of the arms 50. To the end of shaft 33 opposite the crank 32 is fixed a planetary gear wheel which meshes with the continuously turning gear 45. Also fixed to the shaft 33 is a fly 60, the blades of which are adapted to coact with a stop pin 65 which extends inwardly from the frame plate 2.

The operation of the above-described mechanism is as follows:

As the driving gear 45 rotates continuously in the direction indicated by the arrow (Fig. 2), it tends to rotate the gear 55 and shaft 33. However, the stop pin 65 prevents such rotation of the shaft and gear by engaging the lower arm of the fly 60. Consequently, the gear wheel 45 lifts and carries along with it the gear 55, the shaft 33, the crank 32 and the fly 60. Thus so long as the lower arm of the fly engages the pin 65, the shaft 33 and its associated parts have a substantially translational movement upwardly. During this movement, the pin 34 rides substantially freely upwardly in the slot 3| because the crank arm 32 is substantially horizontal, and thus no movement is imparted to the arm 30 and the tube I0.

However, when shaft 33 has been raised sufficiently, the lower end of fly 50 will clear the stop pin and shaft 33 will be free to rotate. Upon such rotation, the crank 32 swings arm 30 rapidly to the right, thus tilting the tube with it and momentarily establishing contact as the mercury flows between the electrodes. As the shaft 33 rotates, it also swings downwardly along the gear 45 so that when the shaft has rotated degrees, it has fallen sufficiently for the other arm of the fly 50 to engage the stop pin 65. When the shaft comes to rest due to this engagement, the arm 32 will be extended in the opposite direction and lie again substantially horizontally with the pin 34 again near the bottom of the slot 3|. Upon continued rotation ofthe driving gear 45', the shaft 33, fly 60, pin 34, etc. are again raised up until the fly is released and the arm 30 swung back to its original position, re-tilting the tube.

In the embodiment shown, electrical contact is made only momentarily on each tilting of the tube. However, by suitable eccentric arrangement of the depressions I3, permanent closure or permanent interruption of the circuit can be effected in one or the other tilted positions of the switch tube.

The mechanism of the invention provides great uniformity in the load on the driving means, because the amount of energy required, (1. e. the lifting of the oscillating shaft to impart potential energy thereto), takes place almost continuously. The force required for tilting the tube is very small because of the balancing action of the oppositely acting springs 23, while the use of the mercury switch 2 affords a high degree of reliability in making contact and permits an inflnite number of switching operations to be performed without any wear on the contacts or electrodes and at a very low energy consumption.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What I claim is:

1. An electrical contact mechanism including in combination a mercury switch tube and means for oscillating said tube comprising continuously operating drive means, a rotatable member actuated thereby for tilting the tube, means for imparting potential energy to said member by raising it while restraining it from rotation and means for releasing the member to rotate and 1..

fall a predetermined distance to tilt the tube.

2. An electrical contact mechanism including in combination a mercury switch tube and means for oscillating said tube comprising a continuously rotatable drive gear, a slide and a crank for tilting the tube, and means for moving the crank along the slide and then rocking it comprising an oscillatory shaft keyed to the crank and geared to said drive gear and means for restraining said shaft from rotation until the crank has moved a predetermined distance along the slide.

3. An electrical contact mechanism including in combination a mercury switch tube and means for oscillating said tube comprising a continuously rotatable drive gear, a slide and a crank for tilting the tube, and means for moving the crank along the slide and then rocking it comprising an oscillatory shaft keyed to the crank and geared to said drive gear and means for restraining said shaft from rotation until the crank has moved a predetermined distance along the slide, and opposed spring means for balancing the tube in either tilted position.

EMIL SPAHN. 

